A man who had been serving 20-40 years for a 2017 Lehighton slaying died Sunday morning, according to prison officials.

Yessy Rivera, 32, was found unresponsive in his cell at State Correctional Institution Benner Township at 9:25 a.m. Sunday, according to a statement from the Pa. Department of Corrections.

He was pronounced dead at Mount Nittany Medical Center in State College at 10:50 a.m.

The jail staff discovered Rivera unresponsive and performed emergency assistance until medical personnel arrived and transported him to the hospital.

State police are investigating the death, and the Centre County Coroner’s office will determine the cause and manner of death.

An autopsy was conducted on Sunday but results were still pending, the coroner’s office said.

Rivera was an inmate at SCI Benner Township since June 2019. In January, Carbon County Judge Steven R. Serfass sentenced Rivera to 20-40 years in prison for the murder of Brian Paul Lindner, 44, of Lehighton.

Rivera pleaded guilty to third degree murder in Lindner’s death. Witnesses said that on April 30, 2017, Rivera cut the man’s throat inside the basement of a home in Lehighton.

At his sentencing, Rivera said expressed remorse over the killing.

“I know I made a big mistake. I know a lot of family members are suffering and hurting,” Rivera reportedly said at the time.

According to the Department of Corrections website, Rivera was the fourth inmate at Benner Township to die in the last 12 months.